Neptuno
| discovered = 1846-09-23 | bgcolour= #D3D3D3 | orbit_ref = — Select "Ephemeris Type: Orbital Elements", "Time Span: 2000-01-01 12:00 to 2000-01-02". ("Target Body: Neptune Barycenter" and "Center: Solar System Barycenter (@0)".)Orbital elements refer to the Neptune barycentre and Solar System barycentre. These are the instantaneous osculating values at the precise J2000 epoch. Barycentre quantities are given because, in contrast to the planetary centre, they do not experience appreciable changes on a day-to-day basis from the motion of the moons. | epoch = J2000 | aphelion = | perihelion = | semimajor = | eccentricity = | period = 164.8 urte | synodic_period = 367.49 egun | avg_speed = 5.43 km/s | inclination = Ekliptikara 6.43° Eguzkiaren ekuatorera 0.72° plano inbariantera (produced with Solex 10 written by Aldo Vitagliano; see also Invariable plane) | asc_node = | arg_peri = | mean_anomaly = | satellites = 14 | physical_characteristics = yes | flattening = | equatorial_radius = Refers to the level of atmospheric pressure 3.883 Lur | polar_radius = 3.829 Lur | mean_radius = | surface_area = 14.98 Lur | volume = 6.254×1013 km3 57.74 Lur | mass = 1.0243×1026 kg 17.147 Lur 5.15×10−5 Eguzki | density = 1.638 g/cm3 | surface_grav = 11.15 m/s2 1.14 g | escape_velocity = 23.5 km/s | sidereal_day = 0.6713 day 16 h 6 min 36 s | rot_velocity = 2.68 km/s 9660 km/h | axial_tilt = 28.32° | right_asc_north_pole = 299.3° | declination = 42.950° | albedo = 0.290 (Bond) 0.41 (geom.) | magnitude = 8.02 to 7.78 | angular_size = 2.2–2.4″ | temperatures = yes | temp_name1 = 1 bar level | min_temp_1 = | mean_temp_1 = 72 K (−201 °C) | max_temp_1 = | temp_name2 = | min_temp_2 = | mean_temp_2 = 55 K | max_temp = | pronounced = | adjectives = | atmosphere = yes | atmosphere_ref = | scale_height = 19.7 ± 0.6 km | atmosphere_composition = 80 ± 3.2% hidrogeno (H2) 19 ± 3.2% helio (He) 1.5 ± 0.5% metano (CH4) ~0.019% hidrogeno deuteruro (HD) ~0.00015% etano (C2H6) Izotzak: amoniako (NH3) ura (H2O) amoniako hidrosulfuroa (NH4SH) metano izotza (?) (CH4•5.75H2O) }} Neptuno Eguzki-sistemako zortzigarren planeta da, sistema horretan dauden gasezko lau erraldoietako bat. Eguzkitik 4.494 milioi km-ra dago. Egitura gaseosoa eta izoztua du. Hidrogenoz eta helioz osatuta dago. Oso bero gutxi jasotzen du eguzkiarengatik, oso urrun dagoelako. 53 K da Neptunoren batez besteko tenperatura. Hala ere, Neptunoren barrutik ateratzen den beroak fenomeno atmosferikoak sortzen ditu, hala nola haizete bortitzak (1.400 km/h). Aurkikuntza J.G. Galle-k aurkitu zuen 1846. urtean, Uranoren ezaugarri orbitalak aztertu ondoren. Sateliteak eta eraztunak Neptunok 14 satelite ezagun ditu, baina 9k bakarrik dute izen ofizial bat. Triton da Neptunoren sateliterik handiena. Eguzki sistemako beste hiru gasezko erraldoiek —Jupiterrek, Saturnok eta Uranok— bezala, Neptunok eraztunak ditu; Saturnoren eraztunak baino ilunagoak eta txikiagoak dira. Neptunoren satelite nagusiak * Naiade * Talasa * Despina * Galatea * Larisa * Proteo * Triton * Nereida Erreferentziak Seidelmann, P. Kenneth; Archinal, Brent A.; A'Hearn, Michael F. et al. (2007). "Report of the IAU/IAG Working Group on cartographic coordinates and rotational elements: 2006". Celestial Mechanics and Dynamical Astronomy 98 (3): 155–180. }} Oharrak Ikus, gainera * Neptuno (mitologia) Kategoria:Neptuno